I Built a Serverless, End-to-End Encrypted Messaging App That Works Without the Internet

What if you could send private messages without WhatsApp, Telegram, internet access, user accounts, or centralized messaging servers?

Meet Eccles Bluechat E2EE — an experimental Android messaging application built around decentralized, Bluetooth-based communication.

Designed with privacy and independence at its core, Eccles Bluechat explores:

• 🔐 End-to-end encryption using ECDH, HKDF-SHA256, and AES-256-GCM.
• 🔑 Android Keystore-backed cryptographic key protection.
• 📡 Serverless, internet-independent Bluetooth messaging.
• 🛡️ Trust-on-first-use (TOFU) identity verification.
• 📁 Encrypted local message and media storage.
• 📞 Bluetooth-based voice and video communication.

No accounts. No advertisements. No tracking. No centralized messaging infrastructure.

This project explores an important engineering question: Can we build meaningful private communication systems without depending on the internet or centralized infrastructure?

This is an open-source engineering experiment, and I'm sharing the architecture, implementation, challenges, and lessons learned.

GitHub: https://github.com/Igwe-Starking/eccles-bluechat-e2ee

Built by Eccles (Igwe Starking).